Evaluation of an Artificial Insemination Programme in a Seasonal Breeding Dairy System through Milk Progesterone

Abstract

In order to evaluate an artificial insemination programme and reproductive efficiency of dairy herds in Uruguay, a survey was conducted with five dairy farms, utilizing a total of 768 lactating Holstein cows. Precision of oestrous detection was assessed by one milk progesterone sample taken on day of breeding and was 11.1%. Two additional samples taken at day 10 and 23 were used to confirm ovulation and early pregnancy. Accuracy of pregnancy estimation by milk progesterone was 70.4%. Reproductive efficiency was determined by the analysis of records. Average intervals from calving to first service were 101 days and to conception 132 days and these were affected by parity, body weight and body condition at calving, but not at breeding, or by milk production. Oestrous detection rates and pregnancy rates were 37.5 and 15.6%, respectively. It was concluded that losses in reproductive efficiency in dairy farms of Uruguay in a seasonal artificial insemination programme were mainly due to unobserved heats, rather than incorrect oestrous detection.

Evaluation of a cow‐side milk progesterone assay and assessment of the positive predictive value of oestrus diagnosis by dairy farmers in New South Wales

“…In a study of dairy cattle in Uruguay, 11.1% of bred cows had a progesterone level greater than 3 mmol/L, enabling a PPV of oestrus diagnosis of 88.9% to be estimated. 12 This is consistent with the farms that had the lowest PPV of oestrus diagnosis in the current study, but is lower than the crude pooled mean PPV calculated across all of the study farms. The Uruguay study authors pointed to the main cause of poor reproductive performance being low oestrus detection rate, not poor PPV of oestrus diagnosis.…”

“…The Uruguay study authors pointed to the main cause of poor reproductive performance being low oestrus detection rate, not poor PPV of oestrus diagnosis. 12 This observation is consistent with the fact that the oestrus detection rate directly affects the submission rate, which in turn affects the pregnancy rate; 4 a reduction in the PPV of oestrus diagnosis does not reduce the herd's submission rate, but rather leads to an increase in dioestrous, anoestrous and pregnant cows being bred and consequently a reduction in the apparent conception rate, which also leads to an increase in the total cost of AI and semen for the herd. These findings are consistent with those of the InCalf project, which lists the oestrus detection rate as one of six key areas that affect herd reproductive performance.…”

“…A wide 95%CI for the intraclass correlation coefficient means that we cannot conclude that the PPVs between farms are similar or different. In a study of dairy cattle in Uruguay, 11.1% of bred cows had a progesterone level greater than 3 mmol/L, enabling a PPV of oestrus diagnosis of 88.9% to be estimated . This is consistent with the farms that had the lowest PPV of oestrus diagnosis in the current study, but is lower than the crude pooled mean PPV calculated across all of the study farms.…”

“…This is consistent with the farms that had the lowest PPV of oestrus diagnosis in the current study, but is lower than the crude pooled mean PPV calculated across all of the study farms. The Uruguay study authors pointed to the main cause of poor reproductive performance being low oestrus detection rate, not poor PPV of oestrus diagnosis . This observation is consistent with the fact that the oestrus detection rate directly affects the submission rate, which in turn affects the pregnancy rate; a reduction in the PPV of oestrus diagnosis does not reduce the herd's submission rate, but rather leads to an increase in dioestrous, anoestrous and pregnant cows being bred and consequently a reduction in the apparent conception rate, which also leads to an increase in the total cost of AI and semen for the herd.…”

Economic opportunity survey of small scale dairy farms of the north west province of Cameroon

“…In the zero grazing system, nutrition may be sufficient to allow heifers to come into oestrus at two years of age (28% of farmers had cows that calved at 25 months of age - Table 4 -but 20% of farms had cows calving at more that four years old) but farmers may fail to detect oestrus accurately too. Inefficient heat detection is usually a limiting factor of reproduction in small scale farms and a human management factor is almost always involved in differences in efficiency of heat detection (Cavestany and Galina 2000). These farmers may need more training on the importance of and the proper approaches to oestrus detection.…”